Method and device for testing the quality of a metallic coating

Abstract

A method and a device for determining a quality of a metallic surface of a metallic substrate, for example a steel or steel alloy substrate, are provided. The device includes a mould, a sheet holder and a die, with which the metallic substrate is formed to produce a drawn test surface. The method and device are used to test the quality of the metallic surface of a metallic coating with a view to a later utilization, especially with a view to a later forming, wherein the metallic substrate is formed at least in-an area of a test surface, wherein a main and an additional shape change of the metallic substrate in the area of the test surface assume predetermined values that are related to the later utilization of the metallic substrate, and wherein the quality of the metallic surface is tested on the test surface after forming.

1. A device for determining a quality of a metallic surface of a metallic substrate, comprising:
 a mould, a sheet holder and a die configured to form a metallic substrate to produce a drawn test surface; and 
 an optical and/or opto-electronic device configured to test a metallic surface of the test surface, 
 wherein the die is configured to form in an area of the drawn test surface of a formed metallic substrate a main shape change that amounts to a 7% maximum change in a first direction of the metallic substrate and an additional shape change that amounts to between a −2% and +2% change, excluding a 0% change, in a second direction of the metallic substrate perpendicular to the first direction, 
 wherein the die has a length of at least 400 mm, a width of at least 250 mm, and a front face with a curvature towards the main shape change with a radius of the curvature from 500 to 2000 mm. 
 
     
     
       2. The device according to  claim 1 , wherein an edge radius between the front face of the die and two longitudinal, length-wise, side faces of the die, running transversely to a direction of the main shape change, amounts to 20 to 80 mm. 
     
     
       3. The device according to  claim 1 , wherein an edge radius between the front face of the die and two latitudinal, width-wise, side faces of the die, running parallel to a direction of the main shape change, amounts to between 2 and 10 mm. 
     
     
       4. The device according to  claim 1 , wherein edges between longitudinal, length-wise, and latitudinal, width-wise, side faces of the die have a corner radius from 50 to 100 mm. 
     
     
       5. The device according to  claim 1 , wherein the mould has two corrugations, running transversely to a direction of the main shape change and arranged on both sides of a recess of the mould. 
     
     
       6. The device according to  claim 1 , wherein different drawing depths are permanently adjustable. 
     
     
       7. The device of  claim 1 , wherein the main shape change is defined by a curvature of the front face of the die. 
     
     
       8. The device of  claim 3 , wherein the edge radius substantially prevents a metal flow movement towards the additional shape change. 
     
     
       9. The device of  claim 4 , wherein the edge radius substantially prevents a metal flow movement towards the additional shape change.